The present invention generally relates to indoor air conditions. The invention particularly relates to botanical air filtration systems and methods suitable for use in buildings and other enclosed spaces.
Tightly sealed buildings have a tendency to suffer from poor air quality, often from the buildup of various pollutants. Major pollutants are usually categorized to be inorganic, organic or biological. Typical inorganic and organic indoor air pollutants include, but are not limited to, tVOC, formaldehyde, toluene, carbon dioxide, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Research into indoor air quality particularly focuses on volatile organic compounds (VOCs), which are a group of 50-300 different chemical substances that are organic and volatile at room temperature with a vapor pressure greater than 0.074 mmHg at 20° C. and can be divided in aldehydes, alcohols, aliphatic hydrocarbons, halogenated hydrocarbons and ketones. Indoor sources for common VOCs include, but are not limited to, commercial products like cleaning liquids, hobby supplies, cosmetics, paintings, adhesives, furniture, building materials, emissions, and tobacco smoke. Biological contaminants mainly include viruses, bacteria, fungi, and mold spores which either grow indoors or are supplied by fresh outdoor air.
Poor indoor air quality can have significant negative effects on individuals. Methods for improving indoor air quality are generally based on limiting the concentration of pollutants involve maximizing ventilation rates and air distribution, removing pollutant sources, and/or cleaning (filtering) the air. A current solution to poor indoor air quality is dilution of the indoor air with outdoor ventilation air, for example, by combining recirculated air with about twenty percent outdoor ventilation air. Units for this purpose include what are referred to as energy recovery ventilators (ERVs), which draw fresh air from outside a building and exhaust air from inside the building, and exchange energy between the two streams to precondition the incoming fresh air. The cost of heating or cooling the outdoor ventilation air can represent between 10 and 20 percent of the total energy consumption of a building. Alternatively or in addition to air ventilation, filtration methods may be used to remove pollutants from the air. Filtration is a physical pollutant removal mechanism commonly used to clean indoor air in commercial heating, ventilation, and air conditioning (HVAC) systems. Various methods of filtering air are well known in the art. However, filtration systems may be expensive to operate and, even with the use of current filtration systems, air ventilation is often still needed to provide suitable indoor air quality.
In view of the above, it can be appreciated that there is an ongoing desire for systems and methods for improving indoor air quality, particularly systems and methods that have reduced energy and operation costs.